A 500-year tale of co-evolution, adaptation, and virulence: Helicobacter pylori in the Americas.

Helicobacter pylori is a common component of the human stomach microbiota, possibly dating back to the speciation of Homo sapiens. A history of pathogen evolution in allopatry has led to the development of genetically distinct H. pylori subpopulations, associated with different human populations, and more recent admixture among H. pylori subpopulations can provide information about human migrations. However, little is known about the degree to which some H. pylori genes are conserved in the face of admixture, potentially indicating host adaptation, or how virulence genes spread among different populations. We analyzed H. pylori genomes from 14 countries in the Americas, strains from the Iberian Peninsula, and public genomes from Europe, Africa, and Asia, to investigate how admixture varies across different regions and gene families. Whole-genome analyses of 723 H. pylori strains from around the world showed evidence of frequent admixture in the American strains with a complex mosaic of contributions from H. pylori populations originating in the Americas as well as other continents. Despite the complex admixture, distinctive genomic fingerprints were identified for each region, revealing novel American H. pylori subpopulations. A pan-genome Fst analysis showed that variation in virulence genes had the strongest fixation in America, compared with non-American populations, and that much of the variation constituted non-synonymous substitutions in functional domains. Network analyses suggest that these virulence genes have followed unique evolutionary paths in the American populations, spreading into different genetic backgrounds, potentially contributing to the high risk of gastric cancer in the region.

Dietary and anthropometric indicators of nutritional status in relation to Helicobacter pylori infection in a paediatric population.

It has been postulated that Helicobacter pylori infection could affect growth and appetite, consequently influencing body weight. Therefore, the association between H. pylori infection and the dietary and anthropometric indicators of nutritional status of a paediatric population were investigated. A total of 525 children (aged 4-16 years) who were referred to the gastroenterology unit of the Sor Maria Ludovica Children's Hospital from Buenos Aires, Argentina, were enrolled and completed an epidemiological questionnaire. H. pylori infection was diagnosed using the ¹³C-urea breath test (¹³C-UBT). Height and weight were assessed for calculation of anthropometric indicators. Energy and macronutrient intakes were estimated by 24 h dietary recall. Data analysis was performed using a χ² test, a Student's t test, a Mann-Whitney U test and linear and logistic regressions. The prevalence of H. pylori infection was 25·1 % (with a mean age of 10·1 (SD 3·1) years). A tendency towards lower energy, carbohydrate, protein and fat intakes was observed in infected patients; however, it was not associated with H. pylori infection in any of the evaluated age groups (4-8, 9-13 and 14-16 years). Underweight, stunting, overweight and obesity were also not associated with the infection. Although height-for-age and BMI-for-age Z scores tended to be lower in infected patients, the differences between H. pylori-positive and H. pylori-negative children were not statistically significant. In conclusion, H. pylori infection was not associated with dietary intake or with anthropometric indicators in the present population of children with gastrointestinal symptoms; however, an increased sample size would be needed to confirm the observed tendency towards lower dietary intake and lower anthropometric indicators of nutritional status in H. pylori-infected children.

Decreasing trend of Helicobacter pylori infection in children with gastrointestinal symptoms from Buenos Aires, Argentina.

BACKGROUND: Helicobacter pylori infection is declining in developed and developing countries. The aim of this study was to retrospectively evaluate over an 8-year period the rate of H. pylori infection in children with gastrointestinal symptoms from Buenos Aires, Argentina. MATERIALS AND METHODS: We reviewed the records of children referred from 2002 to 2009 to the gastroenterology unit of the Children Hospital "Superiora Sor Maria Ludovica" for evaluation of upper gastrointestinal signs and symptoms in which the (13) C-urea breath test was performed to diagnose H. pylori infection and a sociodemographic questionnaire was obtained. RESULTS: Records of a total of 1030 children and adolescents with a mean age of 9.99 years were included in the analysis. We found an H. pylori prevalence of 41.2% (95% CI, 36.9-46.0%) for the triennium 2002-2004, dropping to 26.0% (95% CI, 20.7-31.8%) in the triennium 2007-2009. CONCLUSION: Our results showed a significant decrease in H. pylori infection rates from children referred for upper gastrointestinal symptoms evaluation from 2002 to 2009, following the H. pylori epidemiologic trend reported in other countries.

Novel gastric helicobacters and oral campylobacters are present in captive and wild cetaceans.

The mammalian gastric and oral mucosa may be colonized by mixed Helicobacter and Campylobacter species, respectively, in individual animals. To better characterize the presence and distribution of Helicobacter and Campylobacter among marine mammals, we used PCR and 16S rDNA sequence analysis to examine gastric and oral samples from ten dolphins (Tursiops gephyreus), one killer whale (Orcinus orca), one false killer whale (Pseudorca crassidens), and three wild La Plata river dolphins (Pontoporia blainvillei). Helicobacter spp. DNA was widely distributed in gastric and oral samples from both captive and wild cetaceans. Phylogenetic analysis demonstrated two Helicobacter sequence clusters, one closely related to H. cetorum, a species isolated from dolphins and whales in North America. The second related cluster was to sequences obtained from dolphins in Australia and to gastric non-H. pylori helicobacters, and may represent a novel taxonomic group. Dental plaque sequences from four dolphins formed a third cluster within the Campylobacter genus that likely represents a novel species isolated from marine mammals. Identification of identical Helicobacter spp. DNA sequences from dental plaque, saliva and gastric fluids from the same hosts, suggests that the oral cavity may be involved in transmission. These results demonstrate that Helicobacter and Campylobacter species are commonly distributed in marine mammals, and identify taxonomic clusters that may represent novel species.

Helicobacter spp. other than Helicobacter pylori.

Over the last 12 months, new insights into the association of non-Helicobacter pylori Helicobacters with a range of human diseases in children and adults, including hepatobiliary disease, Crohn's disease, sepsis, and gastric disease were published. Studies investigating the presence of non-H. pylori Helicobacters in domestic animals reinforce previous findings that cats and dogs harbor gastric Helicobacter species and thus may be an important source of these organisms in humans. The confounding effect of enterohepatic Helicobacters on the outcome of biomedical research was investigated in several studies and led to recommendations that animals should be screened prior to performing experiments. A number of important and novel investigations regarding pathogenic mechanisms and immune responses to enterohepatic Helicobacters were conducted. Genomic advances in non-H. pylori Helicobacters included description of the complete genome of Helicobacter canadensis, delineation of two Helicobacter bilis genomospecies, and identification of a novel cis-regulatory RNA. New insights concerning growth conditions, biochemical characterization, and the effect of certain dietary compounds on Helicobacter spp. have also been reported.

Iron, zinc, and copper nutritional status in children infected with Helicobacter pylori.

OBJECTIVE: : Helicobacter pylori colonizes the gastric mucosa of about half of the world's population and it has been related to extragastrointestinal diseases. The present study sought to evaluate the association between H pylori infection and iron, zinc, and copper nutritional status in symptomatic children. PATIENTS AND METHODS: : A cross-sectional study was carried out in 395 children (4-16 years) with upper gastrointestinal symptoms, who were tested for H pylori infection by the C-urea breath test. Iron status was determined by hemoglobin, serum ferritin, and serum transferrin receptors. Copper and zinc serum concentrations were also evaluated. Epidemiological data, dietary assessment, and anthropometric indicators were analyzed as potential confounding factors. RESULTS: : Prevalence of H pylori infection was 24.3%. Anemia and iron deficiency (ID) were found in 12.0% and 14.3% of the H pylori-positive and 8.9% and 11.0% of the H pylori-negative children, respectively. There was no association between H pylori infection and anemia (odds ratio = 1.54 [95% confidence interval [CI] 0.73%-3.24%]) or ID (odds ratio = 1.35 [95% CI 0.67-2.70]). Crude beta coefficients showed that H pylori has no significant effect on hemoglobin, serum ferritin, serum transferrin receptors, copper, and zinc concentrations. However, adjusted results suggested that H pylori-infected children had an increase of 9.74 microg/dL (95% CI 2.12-17.37 microg/dL) in copper concentrations. CONCLUSIONS: : This study revealed that H pylori infection was not associated with iron deficiency, anemia, or zinc concentrations; however, a positive relation with copper status was found after adjusting for confounding factors. The contribution of H pylori infection to higher copper concentrations needs to be confirmed by additional studies.

Effect of a probiotic food as an adjuvant to triple therapy for eradication of Helicobacter pylori infection in children.

OBJECTIVE: Current recommendations for treatment of Helicobacter pylori infection include a proton pump inhibitor in combination with two antibiotics. We evaluated the potential activity of a probiotic food as an adjuvant to antibiotic triple therapy for eradication of H. pylori infection in children from Buenos Aires, Argentina. METHODS: Sixty-five children who tested positive for H. pylori, as diagnosed by (13)C-urea breath test and endoscopy, were included in this study. Patients were randomized to receive 1-wk triple therapy plus probiotic food (treated group) or milk placebo (control) that was administered for 3 mo. Probiotic food consisted of 250 mL of a commercial yogurt containing Bifidobacterium animalis and Lactobacillus casei (10(7) colony-forming units/mL). Post-treatment urea breath test controls were performed 1 and 3 mo after the end of triple therapy. RESULTS: We found no significant differences in H. pylori eradication rates (ERs) at 1 and 3 mo between the treated group (ER = 45.5% and 42.4%) and the control group (ER = 37.5% and 40.6%). Relative risks between groups were 0.87 (95% confidence interval 0.58-1.32, P = 0.345) in the first month and 0.97 (95% confidence interval 0.64-1.46, P = 0.542) in the third month. CONCLUSIONS: We could not demonstrate an adjuvant effect of the studied probiotic food to triple therapy in the eradication of H. pylori infection in children in Buenos Aires, Argentina. However, we found lower ERs than those reported for the same therapeutic scheme in developed countries, indicating that bacterial resistance and alternative therapeutic strategies should be studied.

Quality control validation for exogenous natural surfactant labeled with 99mTc.

OBJECTIVE: Exogenous natural surfactant (ENS) labeled with 99mTc shows an elevated lung specificity allowing the acquisition of high-quality images for ventilation scintigraphy. METHODS: The methods for 99mTc-ENS quality control (physical properties, pH determination, radiochemical studies, and biologic studies) were evaluated and validated. RESULTS: The physical properties of the nonradioactive precursor and of the radiopharmaceutical were analyzed as general descriptors of the product. The pH of the radiopharmaceutical was determined by using pH test papers, a method described and validated in the United States Pharmacopeia. Chromatographic studies performed using the acetone/Whatman-1 paper system were validated as a method to evaluate the radiochemical purity of the 99mTc-ENS. Biodistribution studies on rats after intratracheal administration were validated as a method to estimate the radiopharmaceutical biodistribution in humans. CONCLUSION: The proposed method for 99mTc-ENS quality control studies and stability studies was evaluated and validated following international standards.

Evidence of Helicobacter sp. in dental plaque of captive dolphins (Tursiops gephyreus).

Gastrointestinal lesions have been extensively reported in wild and captive marine mammals. However, their etiology remains unclear. In humans and other animals, chronic gastritis and peptic ulcers have been associated with Helicobacter sp. Therefore, the aim of our study was to investigate the presence of Helicobacter sp. in the gastric juice, dental plaque, and saliva of marine mammals living in a controlled environment. Five dolphins (Tursiops gephyreus), one killer whale (Orcinus orca), one false killer whale (Pseudorca crassidens), three sea lions (Otaria flavescens), two elephant seals (Mirounga leonina), and two fur seals (Arctocephalus australis) were studied. Saliva, dental plaque, and gastric juice samples were examined for Helicobacter sp. using polymerase chain reaction. None of the gastric juice or saliva samples were positive for Helicobacter sp. However, Helicobacter sp. DNA was detected in dental plaque from two dolphins, suggesting the oral cavity might be a reservoir of this bacterium.